Pre - and post-cracking behaviour of fibre reinforced concrete beams on grade

Abstract

Structural design of strip, combined footings, and raft foundations is commonly based on an elastic subgrade assumption. The subgrade is either assumed to be a continuum or to consist of a series of discrete springs and the foundation is assumed to behave elastically. Experimental verification of the simple case of elastic beam on subgrade reaction is reported in the literature, but the data are not extensive. Furthermore, the data pertaining to concrete beams on elastic subgrade before and after cracking is almost non-existent. Therefore, an experimental program was undertaken to study pre- and post-cracking behaviour of steel fibre reinforced concrete beams on elastic subgrade. Two types of subgrade and different end boundary conditions were studied. The beams were subjected to a concentrated point load at the centre. The results of the experimental program are compared with predictions assuming soil to be represented by a series of discrete elastic springs. The results of this study will also help in developing a better understanding of the soil-structure interaction of fibre reinforced concrete slabs on grade, which are being increasingly used in industrial warehouses.